Patent application title: Glare reduction

Abstract:

The driver of a vehicle (10) is protected from glare caused by the bright
lights of an oncoming vehicle at night, or by the Sun lying low in the
sky. The vehicle windshield (20) is divided into pixels (42) whose
transparency can be reduced. The transparency of a limited area of the
windshield is controlled by reducing the transparency of windshield
pixels that lie along the light path (32) of bright light that passes
through an area (34) of the windshield to the driver's eyes. In one
system, a small sensor (44) includes a sensor plate (50) with an array of
sensor pixels (54), and a lens (56) that forms an image of a forward
portion of the environment on the sensor pixel array. An electronic
circuit (70) couples sensor pixels to corresponding windshield pixels,
and reduces the transparency of windshield pixels when corresponding
sensor pixels are brightly illuminated. In another system, a sensor is
provided that senses a finger (84) of the driver touching one of the
windshield pixels to reduce the transparency of that window pixel for a
selected time period.

Claims:

1. Apparatus for use in a vehicle to protect a driver, whose eyes are at a
predetermined position, from bright lights originating from point-like
source, including a windshield through which a driver views an
environment area of the environment that is generally forward of the
vehicle, said windshield having multiple windshield pixels whose
transparency and opacity can be varied, comprisinga sensor having a
sensor area containing multiple sensor pixels, a lens that forms an image
of said environment area onto said sensor area, and a circuit coupled to
said multiple sensor pixels and to said windshield pixels that controls
the transparency of each of said windshield pixels in accordance with the
amount of light falling on corresponding ones of said sensor pixels,
without determining the direction of light from said source.

2. (canceled)

3. The apparatus described in claim 1 wherein:said circuit that controls
the transparency of windshield locations reduces the transparency of an
area of said windshield that occupies no more than 5% of the windshield
area and that is horizontally elongated in order to block light from
reaching each of the driver's eyes.

4. The apparatus described in claim 1 wherein said windshield locations
are windshield pixels, and wherein:said means for controlling the
transparency of windshield pixels decreases the transparency of
windshield pixels that lie within an angle of at least 3.degree. along a
line extending from a point halfway between the driver's eyes toward the
windshield to reduce light at both eyes of the driver.

5. (canceled)

6. Apparatus for use in a vehicle to avoid exposing a driver to glare,
where the driver's eyes have a center located at a predetermined eye
position with respect to the vehicle windshield, and where the glare is
caused by a bright light that passes along a path through the windshield
to said eye position, wherein:said windshield has multiple areas whose
transparency can be reduced; and includinga sensor which has a sensor
area and a lens that forms an image of the environment that can be seen
through at least portions of said windshield, onto said sensor area with
parts of said sensor area each corresponding to areas of said windshield;
anda circuit that detects high relative illumination of limited areas of
said sensor area and that reduces the transparency of corresponding areas
of said windshield.

7. Apparatus for use in a vehicle to avoid exposing a driver to glare,
wherein:said windshield has multiple areas whose transparency can be
reduced; and includinga sensor that senses the driver manually touching
one of said windshield multiple area and a circuit coupled to said sensor
that reduces the transparency of that windshield area that is touched by
the driver.

8. The apparatus described in claim 7 wherein:said circuit is constructed
to maintain said windshield area that was touched, at a reduced
transparency only for a predetermined time period.

Description:

BACKGROUND OF THE INVENTION

[0001]Two of the most common sources of glare are the headlights of an
oncoming vehicle in an adjacent lane, and the Sun when it cannot be
blocked by a sun visor. Apparatus that enabled a driver to block these
and other sources of glare would be of value.

SUMMARY OF THE INVENTION

[0002]In accordance with one embodiment of the invention, an apparatus is
provided that can be activated to block glare that otherwise would reach
the eyes of a vehicle driver from a region of the environment normally
viewable through the windshield (or even the driver side window). The
apparatus includes a windshield with pixels whose transparency, can be
varied, and means for reducing the transparency of pixels that lie
approximately between a glaring light source and the driver's eyes while
not reducing the transparency of the rest of the windshield. The rest of
the windshield remains highly transparent so the driver can clearly view
the road area.

[0003]In one system, the means for reducing transparency includes a small
sensor with a sensor area having multiple sensor pixels, and a lens that
forms an image of the viewed environment region onto the sensor area.
Each sensor pixel corresponds to a predetermined windshield pixel. The
apparatus also includes a circuit that reduces the transparency of those
windshield pixels whose corresponding sensor pixels are brightly
illuminated (compared to the rest of the sensor area). The windshield
area whose transparency is reduced, is preferably horizontally elongated
to block glare from both eyes of the driver.

[0004]In another system, windshield sensors are provided that sense when
the driver's finger touches a particular area of the windshield. A
circuit reduces the transparency of the windshield area that was touched.
The reduction in transparency continues for a short period such as 20
seconds when windshield areas near the bottom of the windshield left side
are touched that may imply the presence of glare from an oncoming
vehicle. The reduction in transparency may continue for a longer period
such as two minutes when a windshield area near the top of the windshield
is touched that implies glare from the Sun.

[0005]The novel features of the invention are set forth with particularity
in the appended claims. The invention will be best understood from the
following description when read in conjunction with the accompanying
drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]FIG. 1 is a partial isometric view of a driver in a vehicle who
experiences glare from an oncoming vehicle.

[0007]FIG. 2 is a front elevation view of the driver of FIG. 1, and
showing a sensor that can control the reduction of glare.

[0008]FIG. 3 is a partial isometric view of the sensor of FIG. 2.

[0009]FIG. 4 is a side elevation view of the driver and windshield of FIG.
1, showing the vertical angle of light from a source of glare.

[0010]FIG. 5 is a schematic view of a circuit that is connected to the
sensor of FIG. 3 and the windshield of FIG. 2, and that controls the
transparency of windshield pixels according to the output of the sensor.

[0011]FIG. 6 is an isometric view of a driver in a vehicle, who is
touching a windshield in a system of another embodiment of the invention,
to block glare from the Sun.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0012]FIG. 1 illustrates a portion of a vehicle 10 and a driver 12 who is
driving the vehicle at night along a road 14. The driver is viewing a
portion 16 of the environment through the windshield 20 of the vehicle.
The drivers's eyes 22, 24 are located at a constant known position in the
vehicle (although this can be varied, especially in height). An oncoming
vehicle 30 has headlights in a "high-beam" position that produce light
beams 32. Light that passes through a horizontally elongated area 34 of
the windshield normally would reach the drivers eyes and produce glare.
In accordance with the present invention, a region 36 of the windshield
has its transparency reduced to prevent the driver from experiencing
glare. The rest of the windshield remains fully transparent, so the
driver continues to view the environment portion that he usually views
through the windshield so he can drive safely. The headlights from an
oncoming vehicle, and the Sun, each can be considered to be a point-like
source, because most light from them can be blocked from the driver's
eyes by reducing the opacity of a windshield area that is no more than 5%
of the windshield area.

[0013]FIG. 2 shows the driver and a portion of the windshield, and shows a
part 40 of the windshield divided into windshield pixels 42. The figure
also shows a small sensor 44 that controls the windshield portion 40 to
reduce the transparency (which is the same as to increase the opacity) of
selected pixels of the windshield. FIG. 3 shows that the sensor 44
includes a plate 50 (e.g. a PCB) with a sensor area 52 thereon containing
multiple sensor pixels 54. Each sensor pixel corresponds approximately to
a windshield pixel. A lens 56 of the sensor forms an image onto the
sensor area 52, of a part of the environment portion seen through the
windshield, that corresponds to the part 40 of the windshield whose
transparency can be decreased. FIG. 5 shows a circuit 70 that receives
the output of each sensor pixel 54 and controls the transparency of
corresponding windshield pixels 42.

[0014]It is possible to provide a one-to-one correlation between each
sensor pixel such as 54A and a windshield pixel such as 42A, so when a
high level of light is detected at 54A, the circuit reduces the
transparency of windshield pixel 42A. However, it is also possible to
vary the transparency of more than one windshield pixel when a
corresponding sensor pixel is subjected to glare, or to choose a
windshield pixel according to the outputs of a plurality of sensor
pixels. For example, if the windshield pixels and sensor area pixels are
each of a square shape, it may be desirable to reduce the transparency of
not only a corresponding windshield pixel, but also of the windshield
pixels on horizontally opposite sides of the corresponding windshield
pixel to block light to both eyes of the driver. FIG. 4 shows that light
beams may pass along an angle of no more than about 1° from the
source 62 to the driver 12, but the window pixels may be large enough, or
enough small window pixels may have their transparency reduced, that
transparency is reduced along an angle A of at least 3° degrees
from a point halfway between the driver's eyes.

[0015]A determination of what constitutes a light source bright enough to
create a glare, is preferably based upon the average intensity of light
in the viewed environment portion at that time. This can be determined by
averaging the output of all sensor pixels, or by taking the output of a
simple sensor that is directed at the environment forward of the vehicle.
For a bright oncoming vehicle headlight at night when the average pixel
output is low, it requires a much less intense light source to cause a
reduction in transparency of a window pixel(s), than the brightness of
the Sun during the day when the average pixel output is much higher.

[0016]The amount of light that is blocked when a window pixel transparency
is to be reduced, is preferably as least of the same order of magnitude
as the percent of light blocked by dark sunglasses. It is also possible
to reduce, to a smaller extent, the transparency of window pixels that
lie around a window pixel that corresponds to a sensor pixel that has
been brightly illuminated. This reduces the glare for a driver even if
the driver's eyes are not precisely aligned with the center pixel. In
that case, a driver then may shift his/her body slightly to center
his/her eyes on the center pixel if the supposed driver position has not
been adjusted to lie at the center of the eyes of the actual driver.
Preferably, the system contains a switch 72 (FIG. 1) that a driver can
operate to energize the glare-reduction system of the invention, so it
operates only when the driver senses glare or that glare is approaching,
and afterward the driver de-energizes the system. The system does not
reduce transparency when the window pixels are not energized. The area
covered by pixels can be increased to block glare cause by reflections of
the sun from another vehicle, but this usually is not as annoying.

[0017]FIG. 6 shows another system 80 for reducing driver glare, wherein
the driver 82 extends a finger 84 so the fingertip touches a location 86
on the inside of the window where the driver sees glaring light coming
from, such as from the sun S. This causes a reduction of the transparency
of that location of the window, and preferably an additional limited area
around the touched location. A variety of devices are available to detect
the location where a person touches a screen. One example which can be
used for a largely flat windshield area is a device 90 that directs light
beams 92, 94 in largely perpendicular directions across the inside of the
windshield. Detectors 100, 102 detect the two thin largely perpendicular
beams that are interrupted by a finger touching (or lying very close to)
the window and reduce the transparency of a pixel at the location being
touched.

[0018]The reduction in transparency continues for a period of time such as
several seconds to several minutes or longer. For example, if the touched
location is near the lower left part of the windshield and the average
light from the environment is low, this indicates that glare comes from
the headlights of an oncoming vehicle. In that case, it may be sufficient
to block that area for several seconds. If the touched area is near the
top of the windshield and the average light in the environment is high,
this indicates that the light is from the Sun, and it may be desirable to
continue blocking the touched area for a longer period such as two
minutes. A driver who notices that he/she is on a curved road, may touch
the windshield along a line, so that light from the Sun is blocked even
as the apparent Sun position changes. When the glare is from the
headlights of an oncoming vehicle, the driver may touch a line area on
the windshield to block light as the oncoming vehicle approaches.

[0019]Although most annoying light is on a path to pass through the
windshield 20 (FIG. 1) of the vehicle, annoying light also can be
received through the driver side window 110, especially sunlight that
heats and may burn the driver's skin. The driver side window can be made
so the entire side window or the upper two-thirds of it is blocked, such
as automatically by a sensor that senses sunlight that appears to pass
through the side window to anywhere on the driver, or by the driver
touching the side window (possibly after operating a switch similar to 72
of FIG. 1).

[0020]Thus, the invention provides an apparatus or system for reducing
glare for drivers, especially glare from headlights on a "high-beam"
setting of an oncoming vehicle, and from the Sun. The system includes a
windshield through which a driver views the environment forward of the
vehicle, and with at least limited areas of the windshield being
controllable to have a reduction in transparency. The windshield
preferably contains a plurality of small pixels, each constituting less
than 10% of the windshield area, and each being selectively controllable
to have a reduced transparency. In one system, a sensor has a sensor area
with sensor pixels on which an image of the forward-looking environment
is focused. A circuit connected to sensor and window pixels reduces the
transparency of window pixels whose corresponding sensor pixels have been
exposed to bright light. In another system, a detector detects a location
where a driver has touched the inside of the windshield, and reduces the
transparency of a corresponding location on the windshield.

[0021]Although particular embodiments of the invention have been described
and illustrated herein, it is recognized that modifications and
variations may readily occur to those skilled in the art, and
consequently, it is intended that the claims be interpreted to cover such
modifications and equivalents.